Strategic Science and Technologies LLC Announces Completion of its Phase 1 Clinical Trial for SST-6006, a First-in-Class Topical Sildenafil Product Candidate Being Developed for the Treatment of Erectile Dysfunction in Men

  • SST-6006 was well tolerated in healthy subjects
  • SST-6006 successfully delivered sildenafil through the skin and into the local penile tissue
  • SST-6006 was systemically absorbed into the blood stream, but at significantly reduced levels compared to oral sildenafil

CAMBRIDGE, Mass.--()--Strategic Science and Technologies LLC (SST), a clinical-stage biotechnology company developing novel first-in-class topical formulations of known pharmaceutical products, announced today the successful completion of its Phase 1 clinical trial of SST-6006, its first-in-class topical sildenafil product candidate for treatment of men with erectile dysfunction (ED). The Phase 1 trial for the investigational drug was designed to assess the safety, tolerability and pharmacokinetics of SST-6006 in healthy men when applied topically directly to the entire penis. A cohort of subjects also received a single oral dose of sildenafil to allow for a comparison between SST-6006 and oral sildenafil.

“These promising results provide additional clinical validation of our KNOSIS™ platform and our ability to successfully deliver therapeutic doses of highly-charged molecules through the skin and into the target tissue,” noted Eric T. Fossel, Ph.D., Scientific Founder and Chief Executive Officer of SST. “We look forward to initiating Phase 2 clinical trials this year to demonstrate the efficacy of SST-6006 in patients with the goal of commercializing a safe and effective topical OTC product for men with ED.”

SST-6006 was found to be well tolerated, with a significantly reduced number of side effects compared to oral sildenafil. All side effects were mild and transient in nature. The peak concentration of sildenafil detected in the blood after a single application of SST-6006 (formulated to deliver 50 mg of sildenafil) was more than twenty-fold lower than what was detected from a 50 mg oral dose of sildenafil. The presence of sildenafil in the blood from SST-6006 confirms successful delivery of sildenafil across the skin. SST intends to demonstrate in its development program that the very low systemic absorption of sildenafil from SST-6006 application, compared to oral sildenafil, will significantly reduce the side effects long associated with oral phosphodiesterase type-5 (PDE-5) inhibitors. These data support SST’s efforts to demonstrate that a single application of SST-6006 will deliver a concentration of sildenafil to the local target tissue (penis) that is equal to or greater than that delivered from a single 50 mg oral dose of sildenafil.

“With a growing concern about systemic side effects associated with the current oral forms of PDE-5 inhibitors, a topical treatment approach such as SST-6006 could enable patients with ED to benefit from a local therapeutic dose of sildenafil directly into the penile tissue while reducing the risk of unwanted systemic side effects,” commented Irwin Goldstein, M.D., Director of Sexual Medicine at Alvarado Hospital and Director of San Diego Sexual Medicine. “I look forward to continuing my work with SST and its novel delivery technology to positively impact sexual health in both men and women.”

About the Clinical Trial

The SST-6006 Phase 1 clinical trial was an open-label, single-dose, randomized, parallel-group, cohort design. Subjects were randomized to receive either a single dose of oral sildenafil or a single topical application of SST-6006 applied to the penis. Safety assessments included physical examination, clinical laboratory evaluations, ECG, and adverse events. Pharmacokinetic analyses to determine concentrations of sildenafil in plasma were completed at pre-specified time points from pre-dose up to 32 hours post-dose.

About Erectile Dysfunction

Erectile dysfunction (ED), a sexual dysfunction affecting an estimated 13-20% of men aged 40 to 80, is characterized by the inability to develop or maintain an erection of the penis during sexual performance. Phosphodiesterase type-5 (PDE-5) inhibitors are considered the standard-of-care in first-line ED treatment. Oral PDE-5 inhibitors such as sildenafil have been administered as treatments for ED for over 15 years and have made a significant impact in the sexual well-being of patients. However, because oral PDE-5 inhibitors are currently only available as a prescription drug and have well documented side effects, the vast majority of patients with ED do not receive oral PDE-5 inhibitors. Studies have reported that of the projected 18 million men with ED, only 16% are treated with oral PDE-5 inhibitor therapy.

About SST-6006

SST-6006, developed with SST’s proprietary KNOSIS™ technology, is a patented topical cream product containing 5% sildenafil citrate by weight. Sildenafil is a specific PDE-5 inhibitor that enhances nitric oxide–mediated vasodilation in the corpus cavernosum by inhibiting cyclic guanosine monophosphate (cGMP) breakdown. When sexual stimulation causes local release of nitric oxide, inhibition of PDE-5 by sildenafil causes increased levels of cGMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. In the oral form, sildenafil is available as a prescription drug. Its use, however, is contraindicated in some men due to its systemic vasodilatory properties that result in decreased supine blood pressure. In patients without these cardiovascular risk factors, mild and temporary side effects include headache, facial flushing, upset stomach and nausea. The FDA-approved labeling for PDE-5 inhibitors also includes warnings about the risk for sudden loss of vision in one or both eyes and sudden decrease or loss of hearing.


SST’s novel topical technology, KNOSIS™, is based on the pioneering work of its Scientific Founder Eric T. Fossel, formerly in the Biochemistry, Biophysics and Radiology Departments at Harvard Medical School. Due to the skin’s highly protective barrier, the stratum corneum, success with topical delivery approaches has been mostly limited to smaller, uncharged molecules. SST's proprietary topical delivery technology overcomes these historical challenges through at least two novel features. First, the KNOSIS formulation technology produces a hostile biophysical environment for the active pharmaceutical ingredient (API), increasing its free energy and creating a positive chemical potential which drives the API from the delivery vehicle into the tissue. Second, this novel formulation prevents the formation of hydrogen bonds between the API and the stratum corneum, which can inhibit the ability of the API to permeate into the tissue. These two complementary actions support SST’s efforts to achieve the desired local therapeutic effect in the target tissue and, due to the minimal uptake of the drug into the bloodstream, greatly reduce or eliminate any known side effects associated with its systemic absorption.

About Strategic Science and Technologies LLC

Strategic Science and Technologies LLC (SST) is a clinical-stage biotechnology company developing first-in-class topical formulations of known pharmaceutical products. SST has been successful in delivering several highly-charged molecules across the skin in therapeutic areas including pain, dermatology, and men’s and women’s sexual health. By working only with FDA-approved drugs, SST utilizes the 505(b)(2) regulatory pathway to accelerate the development of topical formulations and is advancing a portfolio of both OTC and prescription drug product candidates. SST remains privately funded by its original private investors, with a business strategy to partner its products with experienced pharmaceutical companies prior to initiation of the pivotal Phase 3 registration trials.


MacDougall Biomedical Communications
Cory Tromblee, 781-235-3060

Release Summary

Strategic Science and Technologies LLC announces completion of Phase 1 clinical trial for SST-6006, its topical sildenafil product candidate in development for the treatment of erectile dysfunction


MacDougall Biomedical Communications
Cory Tromblee, 781-235-3060